The invention relates to a process for preparing a macroporous synthetic ceramic intended especially as a bone replacement, the ceramic having a controlled interconnection dimension between the pores, as well as a controlled porosity and a controlled pore size.
The processes of the aforementioned type, known from the prior art, have a number of drawbacks.
This is because these processes do not allow the porous architecture of the ceramic obtained to be completely controlled, namely especially to control not only the size and shape of the macropores and their distribution within the ceramic matrix but also the size of the interconnections between macropores.
Now, this lack of control reduces the biological effectiveness of the ceramics, which is characterized, in the case of an application as a bone replacement, by poor bone rehabilitation or, at the very least, partial rehabilitation of the bone replacement.
In addition, heterogeneities in the mechanical behaviour, especially in compression, are often found because of the imperfect reproducibility of the architectures.
Certain processes recommend exerting pressure on the compacted particles intended to form the pores, so as to control the interconnection diameter.
However, this type of process does not allow effective control of the interconnection, which is homogeneous, easily reproducible and modifiable.
Moreover, the structural heterogeneities in the ceramic bone replacements of the prior art often cause variations in the mechanical behaviour.
Because the architectures are not completely controlled, the mechanical strength is often low, particularly in compression. It is necessary to limit the mechanical stresses on the implant and, consequently, to reduce the size of the manufactured components for the purpose of limiting the risk of mechanical failure of the implant/receiving bone system.
The prior art is represented, in particular, by documents WO-A-92/06653, DE-A-4,403,509, DE-A-3,123,460 and WO-A-95/32008.